Work machines are used to perform many different applications in the areas of construction, agriculture, landscaping, and mining. Some work machines are all-wheel drive machines that include hydraulic motors to drive either the front or rear wheels. The hydraulically driven wheels may be driven in an overdrive mode, where they are driven at a faster speed than the non-hydraulically driven wheels; at an equal speed mode where they are driven at the same speed as the non-hydraulically driven wheels; or in an underdrive mode, where they are driven slower than the non-hydraulically driven wheels.
Current all-wheel drive work machines may control the speed of hydraulically driven wheels using a clutch. Japanese Patent No. 2,544,694 B2 describes a truck having a four-wheel drive in combination with hydraulically driven wheels. Each of the hydraulically driven wheels is coupled to a motor via a clutch, which is used to control the speed of the hydraulically driven wheels. Therefore, multiple clutches may be required depending on the number of hydraulically driven wheels. Each clutch can increase the cost and the complexity of the work machine. Additionally, each clutch can become damaged during a work machine operation resulting in a hydraulically driven wheel speed that is inconsistent with operator commands.
Thus, an improved system for controlling the speed of a work machine is desired.